It would depend on how long you stay in Switzerland - the minimum Interrail is 3 days at 149 Euro for an adult
And where you would travel

This is from a few years ago but the links have been updated for 2022
https://www.myswissalps.com/forum/topic/interrail-pass

Peter

Coming from Canada, I normally purchase a Swiss Rail Card, which for around 400 CHF gives me 7 days of unlimited travel on most of the Swiss rail network as well as on most public transit and Postbusses.

I don't know what options are available to residents of other European countries, but you can check MySwitzerland.com for information about your country or
https://www.sbb.ch/de/freizeit-ferien/inspiration/internationale-gaeste/swiss-travel-pass.html

Regards

Mike C

Now that Interrail and Eurail are valid on ALMOST all (not all) rail lines, which used not to be the case, I would say the key really, apart from price, is whether you need non-rail validity (e.g. cable cars, ferries and of course Postautos). Here's where IR / ER are valid nowadays:
https://www.sbb.ch/content/dam/infrastruktur/trafimage/karten/karte-geltungsbereich-InterRail-EuRail.pdf

When visiting Switzerland, usually I am using Spartageskarte (CHF 52.00 per day, 2nd class if purchased in advance). As number of people on the net are using InterRail, I am interested are there any advantage of InterRail, compared to the Spartageskarte.

Pricing of the different offers is not so easy to compare. It depends on how many days you are travelling and if you travel on x days out of y or every day etc.

Another important point is the validity.

• Tageskarten are valid on the same lines as the Generalabonnement. This includes public transport to villages (e.g. Wengen, Hasliberg, Riederalp) and many lake steamers, alpine bus lines and some mountain railways (e.g. Rigi). See the SwissPass validity map
  
• https://www.sbb.ch/content/dam/internet/sbb/de/abos-billette/abonnemente/karte-geltungsbereich-ga-halbtax-stand_d_barrierefrei.pdf.sbbdownload.pdf
  
• Interrail is railway based. No bus, no tram, few reductions on lakes and mountains. Some smaller railway companies don't participate, e.g. SZU, FB. Compare the maps (links above and below)
  
• https://cdn-doc.myswissalps.com/docs/default-source/rail-network-maps/eurail-interrail.pdf?sfvrsn=b9c49bca_58
• Many mountain railways and cableways offer 50% reduction with the Swiss half fare card (dotted lines in SwissPass map). This can quickly sum up to a remarkable sum.
  

Markus, Gürbetal

To avoid confusion, since this is an English language group, it should be clarified that the 'Spartageskarte' is known in English as the Saver Day Pass (and for historical perspective, recorded that it was once reserved for Swiss half fare card holders).
In passing also should be noted that the price is not always CHF52, as the price varies.

For visits purely concentrating on Switzerland, any of the range of passes and other travelcards available for Switzerland (eg Swiss Travel Pass, Swiss half fare card, regional passes) gives overall better coverage of the whole network than does Inter Rail.

The only time Inter Rail is really any better than the passes explained above is if you are covering other countries in the same trip (eg France, Italy)

Inter rail is OK if you just travel on the main lines, which is why it is often used by the locomotive haulage enthusiasts who are mainly interested in main line trains on the 'core' Swiss network.

Personally I have an annual Swiss half fare card so that any time I visit Switzerland, I can get a discounted Saver Day Pass (SDP) in advance, and also jump on any train or bus for 1/2 price if I have an odd day or half day for which I have not preplanned a SDP. This happened on my recent trip when my half fare card was helpful for some incidental travel around Geneva, partly as a result of my Easyjet flight back to UK being delayed from Sunday evening to Monday afternoon!

[moderator's note: please delete old message. Thank you]
Until end July, an offer on SBB 20 or 30 day leisure pass (620- and 840- CHF) :
https://www.sbb.ch/en/travelcards-and-tickets/railpasses/leisure-travelcard.html
One month discounted General Abo 340-CHF :
https://www.sbb.ch/en/travelcards-and-tickets/railpasses/trial-ga.html
Not great value perhaps, but might fit some specific plans.